I. Field of the Invention
The present invention relates to an air filter device in the form of an elongated tubular member, such as, a hose, which may be flexible, having an inlet end and an outlet end for filtration of air passing through the tubular member. The filter device is particularly adaptable for use as an air filter for automobile or truck engines.
II. Prior Art
Air filter devices for internal combustion engines are well known and have been utilized on automobiles and trucks almost from the beginning of the manufacture of vehicles propelled by internal combustion engines. Generally an air filter for an internal combustion engine includes a housing having an inlet end through which air is drawn and an outlet end that is in communication with the engine carburetor or intake manifold. A filter element is positioned within the housing through which air is forced to flow.
For many years the typical air filtration system for an automobile and light trucks consisted of a relatively large circumferential housing having a large relatively flat cover plate that could be removed for the installation of the filter element. The typical filter element used for cars and trucks for many years was in the form of a short length relatively large diameter tubular member sealed on both ends and arranged, when positioned within the housing, for air to flow radially through the filter element from the exterior to the interior, the interior being in communication with the automobile air intake system. Filters of this type function satisfactorily except that the housing is relatively large and takes up considerable space within the engine compartment. As automobiles have been reduced in size and weight to achieve improved fuel economy and have been streamlined to reduce air resistance, the space within engine compartments has become greatly diminished. For this reason in recent years air filters for automobiles have taken on different configurations so as to more readily adapt them to fit within confined and irregular shaped spaces within an engine compartment.
The use of filter housings having an elongated cylindrical shape has become more common as illustrated in U.S. Pat. No. 5,125,940 entitled "In-Line Air Filter Apparatus" and U.S. Pat. No. 5,106,397 entitled "Air Cleaner/Noise Silencer Assembly". Reference may also be had to pending United States application Ser. No. 08/364,617, now U.S. Pat. No. 5,522,909, which describes and illustrates a type of frusto-conical shaped filter element for use in a filter housing.
For additional background information relating to filtration systems, reference may be had to the following U.S. Pat. Nos. 5,263,503; 5,275,636; 5,338,446 and 3,941,697.